package com.example.adminframework.util;

import java.io.UnsupportedEncodingException;
import java.util.Base64;

/**
 * @Date 2020.12.06
 * @Description base工具类
 */

public class Base64Util {

    //转码 参数：值，编码格式
    public static String getEncodeStr(String value, String format) throws UnsupportedEncodingException {
        return Base64.getEncoder().encodeToString(value.getBytes(format));
    }

    //解码 参数：值，编码格式
    public static String getDecodeStr(String value, String format) throws UnsupportedEncodingException {
        return new String(Base64.getDecoder().decode(value), format);
    }

    //base64字符串转byte[]
    public static byte[] base64String2ByteFun(String base64Str) {
        return Base64.getDecoder().decode(base64Str);
    }

    //byte[]转base64
    public static String byte2Base64StringFun(byte[] b) {
        return Base64.getEncoder().encodeToString(b);
    }

    public static void main(String[] args) throws UnsupportedEncodingException {
        String s = "eyJ0eXAiOiJqd3QifQ==.eyJleHBpcmVUaW1lIjoxNjA4Mjg1MjE3NjMwLCJ1c2VySUQiOjEsInVzZXJOYW1lIjoiYWRtaW4ifQ==.eDGM7RxrHLyH4cgxlrEegEBFBDCYI3UIh9UrWDV61BUC9vakpgFWRZHLBcbpLW5TEzy9/1TOZEcefSBAWeZYpwHP+7NcP6WaZO6AOhpW6Pbba46RO6K7MkJaJvZF7/dEbpLcYK6zzfizGKiEzWQ9dA==";
        String encodeStr = getEncodeStr(s, "utf-8");
        System.out.println(encodeStr);
    }

    /**
     * 校验文件大小
     *
     * @param base64 base64
     * @return boolean
     */
    public static boolean checkSize(String base64) {
        //符合条件的照片大小（可配置） 单位：M
        double imgSize = 0.6;
        int length = base64.length();
        //原照片大小
        double size = (double) length / 1024 / 1024 ;
        return size <= imgSize;
    }

    /**
     * 判断是否为图片
     *
     * @param base64 base64
     * @return boolean
     */
    public static boolean isImage(String base64) {
        try {
            String[] str = {"png", "jpg", "jpeg"};
            String[] split = base64.split("/");
            String image = split[1].split(";")[0];
            for (String s : str) {
                if (s.equals(image)) {
                    return true;
                }
            }
            return false;
        } catch (Exception e) {
            return false;
        }

    }

    /**
     * 子符串内容数组
     */
    private static char[] base64EncodeChars = new char[] {
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
            'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
            'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
            'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
            'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
            'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
            'w', 'x', 'y', 'z', '0', '1', '2', '3',
            '4', '5', '6', '7', '8', '9', '-', '_' };

    /**
     * 字节内容数组
     */
    private static byte[] base64DecodeChars = new byte[] {
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 /*62*/, -1, 62/*-1*/, -1, -1/*63*/,
            52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
            -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
            15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63/*-1*/,
            -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
            41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };

    /**
     * 字节转字符
     * @param data
     * 			字节数组
     * @return 字符串结果
     * @author	张晓松
     */
    public static String encode(byte[] data) {
        StringBuffer sb = new StringBuffer();
        int len = data.length;
        int i = 0;
        int b1, b2, b3;
        while (i < len) {
            b1 = data[i++] & 0xff;
            if (i == len) {
                sb.append(base64EncodeChars[b1 >>> 2]);
                sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
                sb.append("??");
                break;
            }
            b2 = data[i++] & 0xff;
            if (i == len) {
                sb.append(base64EncodeChars[b1 >>> 2]);
                sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
                sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
                sb.append("?");
                break;
            }
            b3 = data[i++] & 0xff;
            sb.append(base64EncodeChars[b1 >>> 2]);
            sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
            sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);
            sb.append(base64EncodeChars[b3 & 0x3f]);
        }
        return sb.toString();
    }

    /**
     * 字符串转字节
     * @param str
     * 			字符串数据
     * @return
     * 			字节数组
     * @throws UnsupportedEncodingException
     * @author	张晓松
     */
    public static byte[] decode(String str) throws UnsupportedEncodingException {
        StringBuffer sb = new StringBuffer();
        byte[] data = str.getBytes("utf-8");
        int len = data.length;
        int i = 0;
        int b1, b2, b3, b4;
        while (i < len) {
            do {
                b1 = base64DecodeChars[data[i++]];
            } while (i < len && b1 == -1);
            if (b1 == -1) {
                break;
            }
            do {
                b2 = base64DecodeChars[data[i++]];
            } while (i < len && b2 == -1);
            if (b2 == -1) {
                break;
            }
            sb.append((char) ((b1 << 2) | ((b2 & 0x30) >>> 4)));
            do {
                b3 = data[i++];
                if (b3 == 61) {
                    return sb.toString().getBytes("ISO-8859-1");
                }
                b3 = base64DecodeChars[b3];
            } while (i < len && b3 == -1);
            if (b3 == -1) {
                break;
            }
            sb.append((char) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));
            do {
                b4 = data[i++];
                if (b4 == 61) {
                    return sb.toString().getBytes("ISO-8859-1");
                }
                b4 = base64DecodeChars[b4];
            } while (i < len && b4 == -1);
            if (b4 == -1) {
                break;
            }
            sb.append((char) (((b3 & 0x03) << 6) | b4));
        }
        return sb.toString().getBytes("utf-8");
    }
}
